Honda Prelude Forum - PreludeDriver.com

Hey guys,
Im trying to resurrect my 91si 5spd cause my b21a is shot, i have a jdm b20a and my mechanic is saying that it wont work because the motor mounts wont match up. Ive seen countless 91si's with the swap done. I gotta get my lude on the road, im having withdrawals. Anyone have this problem.

If your B20A is from a JDM 3rd generation Prelude, it will bolt up just fine. The B20A is a different engine than the other B20 engines.

The biggest thing you'll probably have to learn about is the electronics. The distributor is likely different on the JDM engine, and the ECU may be different as well. As far as i know though, there aren't any major roadblocks to getting the engine in.

Whats your saying is exactly what i have researched and read. The only problem i can see is if the engine that got sent to my mechanic was either the Jdm b20 from the accord/vigor or a jdm b20 from the crv. Im gonna try to get over to the garage today to see for myself. Other than the electrical and ecu, i know i need to swap the intake mani, the exhaust mani and possibly a heater hose pipe because its longer on the b20a then my b21.

Sounds like you're really on the right track. I didn't know about the heater hose.

Post up some pics of this swap! I'm sure we'd all love to see your progress.

ill try to post what i can, im actually having some mechanics do it this time since im working alot. I swapped in a b21 last time, but not this time. I dont have a backyard to do it in lol.

91darkness wrote:I dont have a backyard to do it in lol.

That's what living rooms are for.

this was my work place, an older pic, but still shows my pride and joy

Looks pretty straight.

Is that green?

black on black

ok so i just got my car back from the mechanic after what seemed like ages yesterday. Everything swapped over like it was supposed too. I drove it from the shop a mile and a half, but my problem is now my clutch doesnt seem to work today. When the car is off i can put it in all gears, but when the car is running i cant seem to get it in any gears at all. I have bleed the clutch and it does spring back. Any Clue?

If you're sure the fluid is well bled, it's likely the master or slave cylinder of the clutch. Usually the slave cylinder fails first. Have a check around for leaks and any obvious signs of damage. Even if you can't find a leak doesn't mean all is well. If the slave cylinder is really old, they often stop working.

Have someone press the clutch pedal while you watch the clutch arm move. If it doesn't move the needed amount, there is definitely a problem with the master or slave clutch cylinder.

Well, i think it needed bleeding, but i think i made it worse cause i forgot you need at least two people to bleed the clutch. I going to try bleeding again with some aid.

Well.....all the research, time, and money has given me back my prelude. The outcome is ok, i dont know what problems others have gotten into with the b20a swap in, but mine has had some hiccups. This is the facts i have experienced with this swap. Everything has swapped over nicely like the exhaust manifold, intake manifold, and engine mount/brackets from the B21a1. What has not swapped nicely is the manual tranny from the b21a1. The tranny itself and parts have swapped nicely, but changing the gears is like changing gears on a old truck. It gets smoother at times, but still rough. I have to play with it multiple time before i can get it in gear. The mechanics take on it is that, a shim need to be put in to help the clutch engage more. They narrowed it down to that because i have a new clutch master cylinder, clutch slave cylinder and no air in the lines.
Here are my prices:
Slave cylinder-$26.00
Coolant Hoses-$20.00
intake manifold gasket kit-$37.00
transaxle seal x2-$24.00
Heater Hose/clamps-$13.00
radiator fan motor-$90.00
B20A-$915 w/shipping
labor-$1,462
I know its crazy but i love this car. Im going to drive it with the crazy shifting cause i cant afford to have a shim put in.

Nicely done! And thanks for keeping us all up to date.

Pics of the engine!

ill try to post some when i get off of work today or tomorrow.